1. Field of the Invention
This invention relates to a process of forming a quinone-coupled polyphenylene oxide which comprises contacting a polyphenylene oxide, wherein said contacting is carried out with a quinone in the substantial absence of any monophenol reactant and any active oxidative coupling catalyst system. The resulting new polymers have improved color and in combination with styrene resins provide thermoplastic compositions having improved chemical and physical properties.
2. Description of the Prior Art
Self-condensation reactions of certain phenols employing oxygen in combination with an effective oxidative coupling catalyst system to form prior art polyphenylene oxides, are described in various U.S. Pat. applications including Hay's U.S. Pat. Nos. 3,306,879; 3,914,266; application Ser. No. 540,473, filed Jan. 13, 1975; a continuation-in-part of Ser. No. 441,295, filed Feb. 11, 1974. now abandoned; and Olander's U.S. Pat. Nos. 3,956,442; 3,965,069; 3,972,851; and Serial No. 582,910, filed June 2, 1975. All of the Hay and Olander disclosures referenced above are incorporated herein in their entirety by reference.
Cooper's U.S. Pat. No. 3,496,236 discloses the equilibration of polyphenylene oxide and certain phenols in the presence of a phenoxy radical carried out under oxidizing reacting conditions. White's U.S. Pat. No. 3,367,978 discloses the preparation of novel compositions of matter resulting from the reaction of a phenol and a polyphenylene oxide under equilibration reaction conditions, i.e., carried out under oxidizing reaction conditions. All of the Copper and White's disclosures referenced above are incorporated herein in their entirety by reference.
Heretofore, quinone reaction product species known to be most deleterious to the color of prior art polyphenylene oxides have been separated by precipitating the polymer with an anti-solvent for the polymer which is a solvent for the quinone species.
Unexpectedly and advantageously, we have now found that quinones can be reacted with prior art polyphenylene oxides to form useful quinone-coupled polyphenylene oxides. The resulting quinone-coupled polyphenylene oxides are substantially free of quinone color entities and are suited to the manufacture of thermoplastic compositions having improved chemical and physical properties.